Multiple filters affect tree species assembly in mid-latitude forest communities

Abstract

Species assembly patterns of local communities are shaped by the balance between multiple abiotic/biotic filters and dispersal that both select individuals from species pools at the regional scale. Knowledge regarding functional assembly can provide insight into the relative importance of the deterministic and stochastic processes that shape species assembly. We evaluated the hierarchical roles of the α niche and β niches by analyzing the influence of environmental filtering relative to functional traits on geographical patterns of tree species assembly in mid-latitude forests. Using forest plot datasets, we examined the α niche traits (leaf and wood traits) and β niche properties (cold/drought tolerance) of tree species, and tested non-randomness (clustering/over-dispersion) of trait assembly based on null models that assumed two types of species pools related to biogeographical regions. For most plots, species assembly patterns fell within the range of random expectation. However, particularly for cold/drought tolerance-related β niche properties, deviation from randomness was frequently found; non-random clustering was predominant in higher latitudes with harsh climates. Our findings demonstrate that both randomness and non-randomness in trait assembly emerged as a result of the α and β niches, although we suggest the potential role of dispersal processes and/or species equalization through trait similarities in generating the prevalence of randomness. Clustering of β niche traits along latitudinal climatic gradients provides clear evidence of species sorting by filtering particular traits. Our results reveal that multiple filters through functional niches and stochastic processes jointly shape geographical patterns of species assembly across mid-latitude forests.

Constraints on the distribution of species abundances indicate universal mechanisms of community assembly

“…From these data, we extracted 7,795 SADs across multiple taxa (trees, vertebrates, and invertebrates) and different habitats including terrestrial, freshwater, and marine ecosystems (Data S1 provides a complete list of the sources included). The SADs of woody plants from this compilation have already been published by Kubota et al (). Here, we examined all 7,795 SADs.…”

Natural Disturbance-Based Forest Management: Moving Beyond Retention and Continuous-Cover Forestry

“…From the evolutionary point of view, disturbances, which are characterized by region-specific climatic (abiotic) conditions, can be seen as environmental filters. The evolutionary premise of natural disturbancebased management is that adaptations and assemblies of specific species, communities and ecosystems have arisen through multiple environmental filters (Kubota et al, 2018b), prominently driven by natural disturbance, and more recently including anthropogenic disturbance. Thus, ecosystems and landscapes are characterized by resilience and adaptive capacity within the natural range of variation in environmental conditions (Sgrò et al, 2011).…”

Intraspecific Trait Variability Determines Understorey Plant Community Assembly

“…However, most work on plant niche overlap has been done with literature data using averaged trait values (e.g. Schellenberger Costa et al 2018; Kubota et al 2018; Kermavnar and Kurnar 2020). This work has revealed complex and site speci c relationships between the effects of niche and environment, both triggering species cooccurrences (Bar-Massada 2015).…”